<template>
  <!-- 只有总页数大于1时才显示 -->
  <div class="pager-container" v-if="pageNumber > 1">
    <a @click="handleClick(1)" :class="{ disabled: current === 1 }">
      |&lt;&lt;
    </a>
    <a @click="handleClick(current - 1)" :class="{ disabled: current === 1 }">
      &lt;&lt;
    </a>
    <a
      @click="handleClick(n)"
      v-for="n in numbers"
      :key="n"
      :class="{ active: n === current }"
    >
      {{ n }}
    </a>

    <a
      @click="handleClick(current + 1)"
      :class="{ disabled: current === pageNumber }"
    >
      &gt;&gt;
    </a>
    <a
      @click="handleClick(pageNumber)"
      :class="{ disabled: current === pageNumber }"
    >
      &gt;&gt;|
    </a>
  </div>
</template>

<style lang="less" scoped>
@import "~@/styles/var.less";
.pager-container {
  display: flex;
  justify-content: center;
  margin: 20px 0;
  a {
    color: @primary;
    margin: 0 6px;
    cursor: pointer;
    &.disabled {
      color: @lightWords;
      cursor: not-allowed;
    }
    &.active {
      color: @words;
      font-weight: bold;
      cursor: text;
    }
  }
}
</style>

<script setup>
import { ref, computed } from "vue";

const props = defineProps({
  current: {
    type: Number,
    default: 1,
  },
  total: {
    type: Number,
    default: 0,
  },
  limit: {
    type: Number,
    default: 10,
  },
  visibleNumber: {
    type: Number,
    default: 10,
  },
});

const current = ref(props.current);

const pageNumber = computed(() => Math.ceil(props.total / props.limit));

const visibleMin = computed(() => {
  let min = current.value - Math.floor(props.visibleNumber / 2);
  if (min < 1) {
    min = 1;
  }
  return min;
});

const visibleMax = computed(() => {
  let max = visibleMin.value + props.visibleNumber - 1;
  if (max > pageNumber.value) {
    max = pageNumber.value;
  }
  return max;
});

const numbers = computed(() => {
  let nums = [];
  for (let i = visibleMin.value; i <= visibleMax.value; i++) {
    nums.push(i);
  }
  return nums;
});

const emit = defineEmits(["pageChange"]);

const handleClick = (newPage) => {
  if (newPage < 1) {
    newPage = 1;
  }
  if (newPage > pageNumber.value) {
    newPage = pageNumber.value;
  }
  if (newPage === current.value) {
    return;
  }

  current.value = newPage;
  emit("pageChange", newPage);
};
</script>
